ABSTRACT The goal of this proposal is to develop and optimize the technologies and reagents for use of directed and quantitative proteomic approaches in Xenopus. Specifically, we propose a series of feasibility studies based on three proteins, the T-box transcription factors TBX5, the zinc finger transcription factor CASZ1, and the non-receptor protein phosphatase SHP2. We have focused on these proteins based on their evolutionary conservation in sequence, expression, and function, their cellular localization, and the observation that these proteins are causative, or have association with human disease states: patients with Holt-Oram syndrome (HOS), a disease which also affects the heart and limbs, is associated with mis-sense mutations in Tbx5, genome wide association studies have implied a role for Casz1 in hypertension and high blood pressure, and patients with Noonan syndrome, a disease that also affects heart and limb development, frequently is associated with mis-sense mutations in Shp-2. Despite the crucial role for TBX5, CASZ1 and SHP-2 in development and human disease, the molecular mechanisms by which these proteins act in vivo remains to be established. To address these issues and to establish a set of general technologies for the use of directed proteomics approaches in Xenopus we propose to 1) establish a binary transgenic system in Xenopus for the isolation of protein and protein-DNA complexes and 2) establish the technologies, reagents and protocols for directed and quantitative proteomic approaches in Xenopus.